1. Field of the Invention
This invention relates in general to a solid preparation for medicinal tablets, granules, and such, as well as a method of manufacturing it, and more particularly to a solid preparation which contains for a binder or a disintegrant methyl cellulose whose MeO content and aqueous solution viscosity are in specified ranges, as well as a method of manufacturing it.
2. The Prior Art
Solid preparations such as medicinal granules and tablets have advantages in that they are convenient for administering and easy to take.
However, a solid preparation may be worn away during transportation unless it has an adequate hardness; on the other hand if it is too hard then it may not disintegrate and be absorbed after it is inside the body.
In order to improve the hardness and the disintegration properties required of such a solid preparation, it is desirable to improve additives such as binders and disintegrants to be blended in the solid preparation.
Conventionally known substances for the binder of a solid preparation include methyl cellulose, hydroxypropylmethyl cellulose, hydroxypropyl cellulose, and polyvinylpyrolidone (hereafter abbreviated as MC, HPMC, HPC, and PVP).
Of these binders, MC is used as an additive for medicinal drugs which is a stable binder over a wide range of pH.
For example, Japanese unexamined patent publication Tokkai Hei 4-164025 reports to the effect that MC whose 2 wt % aqueous solution is 80 cP or higher at 20.degree. C. can be used for the matrix base agent for controlled release tablets.
Solid preparations are mainly manufactured by the wet granulation method. Depending on the drug, an adequate hardness cannot be obtained by a normal amount of binder. If the amount to be added is increased to solve this problem, then although an increase in the hardness is achieved there is a problem in that the disintegration time in the body becomes longer.
Therefore, the development of a solid preparation containing a binder which quickly disintegrates even if the amount to be added is increased has been desired.
As for the MC, the commercially available low viscosity product has a viscosity of 15 cP, which is high. If this is used to prepare an aqueous solution of the binder such that an adequate hardness can be achieved, then the viscosity will be higher than 600 cP. In general, the viscosity of an aqueous solution used in the wet granulation method is 600 cP or less. Therefore, there is a problem in that this low viscosity product pushes the viscosity of the binder aqueous solution too high and hence denies the option of increasing the amount to be added to the solid preparation.
Furthermore, in the case where the MC is used in a powder form to granulate a solid preparation using water, there is also a problem in that dissolution of the MC powder takes time because of its high viscosity.
Based on the aforementioned problems, the inventors conducted earnest research to obtain a solid preparation which has an adequate hardness and at the same time disintegrates quickly, and discovered that the aforementioned problems can be solved by adding, for a binder or disintegrant, a MC whose MeO content and aqueous solution viscosity are in specific ranges to the solid preparation, thus completing the present invention.
The object of the present invention is to provide a solid preparation which has an adequate hardness and at the same time disintegrates quickly for easy absorption, as well as a method of manufacturing it.